1. Field
This disclosure relates to an electrode for fuel cell, a membrane-electrode assembly including the same and a fuel cell system including the same.
2. Description of the Related Technology
A fuel cell is a power generation system for producing electrical energy through an electrochemical redox reaction of an oxidant and hydrogen included in a hydrocarbon-based material such as methanol, ethanol, or natural gas. Such a fuel cell is a clean energy source with the potential to replace fossil fuels. Fuel cells include a stack of unit cells each configured to produce various ranges of power output. Since a fuel cell may have about four to ten times higher energy density than a small lithium battery, fuel cells may be small and portable power sources.
Representative exemplary fuel cells include a polymer electrolyte membrane fuel cell (PEMFC) and a direct oxidation fuel cell (DOFC), including a direct methanol fuel cell that uses methanol (DMFC) as a fuel. The polymer electrolyte fuel cell has an advantage of high energy density and high power, but also has problems in the need to carefully handle hydrogen gas and the requirement of accessory facilities such as a fuel reforming processor for reforming methane or methanol, natural gas, and the like to produce hydrogen as the fuel gas. A direct oxidation fuel cell, however, has a relatively lower energy density than that of the polymer electrolyte fuel cell, but it has an advantage of easy handling of a fuel. It also has further advantages including being capable of operating at room temperature due to its low operation temperature, and begin able to operate without additional fuel reforming processors.
In one of the above fuel cells, a stack capable of generating electricity generally includes a number of unit cells stacked in multiple layers. Each unit cell is formed of a membrane-electrode assembly (MEA) and a separator (also referred to as a bipolar plate). The membrane-electrode assembly is formed of an anode (also referred to as a “fuel electrode” or an “oxidation electrode”) and a cathode (also referred to as an “air electrode” or a “reduction electrode”) separated by a polymer electrolyte membrane.